/Engine/Source/Runtime/Engine/Classes/Kismet/KismetRenderingLibrary.h
Manually releases GPU resources of a render target. This is useful for blueprint creating a lot of render target that would normally be released too late by the garbage collector that can be problematic on platforms that have tight GPU memory constrains.
static void ReleaseRenderTarget2D ( [UTextureRenderTarget2D](API\Runtime\Engine\Engine\UTextureRenderTarget2D) * TextureRenderTarget )